Thought I wouldn't be happy to stack off PF vs xem, so I flatted.
Then I just called him down as I thought AQ was possible, maybe AJs, and AK.
Wasn't really putting him on a midpair.
Notes to player added

Preflop flat call is fine. You don't feel you have dynamic to stack off and you don't really want to fold from this spot either.

I would definitely call flop/turn.

River you might be able to find a hero-fold. Many villains check back AQ/AJ on a flush river since they are scared you have it. Also there is a possibility villain double barreled flush draw and got there.

I don't hate your call or anything, but maybe postflop stats could help you decide. Perhaps villains river aggression falls off dramatically on the river.

Preflop flat call is fine. You don't feel you have dynamic to stack off and you don't really want to fold from this spot either.

I would definitely call flop/turn.

River you might be able to find a hero-fold. Many villains check back AQ/AJ on a flush river since they are scared you have it. Also there is a possibility villain double barreled flush draw and got there.

I don't hate your call or anything, but maybe postflop stats could help you decide. Perhaps villains river aggression falls off dramatically on the river.

You are right.
But actually AF on river is what gave me the last hint for the call, being:
Flop AF: 3
Turn AF: 2
River AF: 4